PROJECT SUMMARY/ABSTRACT Through the research and training described in this K23 proposal, the PI (Dr. Helseth) will acquire the necessary skills to become an independent clinical researcher focused on designing and evaluating early, substance use (SU) interventions for youth on risky developmental trajectories. Marijuana (MJ) use accounts for 92% of positive drug screens among teens in the juvenile justice system (JJ) and has been linked to future arrests and SU disorders. Due to JJ capacity constraints, court-involved, non-incarcerated (CINI) youth are often referred out for treatment and encounter multiple barriers to community care. Technology-assisted interventions would enable the JJ system to treat CINI youth in-house, without overextending its workforce or resources. Brief, computerized motivational interventions are inexpensive and easy to deliver, and have been shown to reduce teens? MJ and SU. However, effects typically fade after a few months, indicating the need for an adjunct intervention to sustain behavior change. Smartphone apps are an ideal treatment platform for teens: 95% of teens own one, which they use nearly 3 hours each day. Yet the potential of smartphone apps as a means of reducing MJ use in high-risk youth has not been realized. With this 5-year K23, the PI aims to establish the needs and preferences of CINI youth ages 14-17 for an adjunctive smartphone app; examine the app?s feasibility and acceptability; and establish its preliminary efficacy. The Teen Empowerment through Computerized Health (TECH) app, which targets putative intrapersonal and interpersonal mechanisms to promote MJ-related behavior change, will serve as an adjunct to treatment-as-usual (TAU) in the Rhode Island Family Court. Following the Behavior Intervention Theory (BIT) model, qualitative interviews with key stakeholders (n=30) will inform how clinical goals (knowledge, skills, motivation) will map on to TECH usage goals (goal-setting, peer networking), features (expert-moderated forum, notifications) and workflow. Next, 10 CINI youth will beta test the TECH prototype for 1 month, to guide its refinement. Finally, a pilot randomized control trial with 60 CINI youth will test the app for 6 months as an adjunct to TAU (TAU+TECH vs. TAU-only) on MJ and other SU-related outcomes, putative mechanisms of change (i.e., intrapersonal and interpersonal factors), and high-risk behaviors. The PI will work with an accomplished, multidisciplinary mentorship team (Drs. Spirito, Barnett, Becker, and Clark) to master four relevant areas of training: 1) effective MJ and SU interventions for CINI youth; 2) interpersonal mechanisms of adolescent SU; 3) development of technology- assisted behavioral interventions; and 4) qualitative methods for treatment development. The research and training activities outlined in this K23 award contribute to both an important public health concern and the development of a productive and independent research career for the PI. Completion of this study has the potential to advance the field by demonstrating the feasibility, acceptability, and preliminary efficacy of an adjunct technology-assisted intervention to improve outcomes among high-risk, MJ-using CINI youth.